Browsing by Author "Dahl, Olli, Prof., Aalto University, Department of Forest Products Technology, Finland"

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    Application of the refractometer in the measurement and monitoring of brown stock washing
    (Aalto University, 2015) Kopra, Riku; Puunjalostustekniikan laitos; Department of Forest Products Technology; Kemian tekniikan korkeakoulu; School of Chemical Technology; Dahl, Olli, Prof., Aalto University, Department of Forest Products Technology, Finland
    Brown stock kraft pulp washing removes soluble impurities from a pulp suspension, recovers cooking chemicals and incinerates organics for energy recovery (steam and electricity generation). The parameters used to describe the performance of washing or its effectiveness fall into two categories: wash loss, which describes the amount of washable compounds in the pulp suspension which could have been removed in washing, and the dilution factor which represents the net amount of water that is added during washing. The performance of brown stock washing has an effect on many sub-processes like evaporation, oxygen delignification, bleaching and waste water treatment. Washing results can have positive or negative effects on these sub-processes. It is important to find the correct optimal operating point for washing, because without effective washing of kraft pulp production is not economically viable. The starting point for this study was to develop a real-time measurement application for brown stock kraft pulp washing by which means it would be possible to measure washable compounds or their sum parameters in the liquid and pulp streams on a laboratory and mill scale. The next step was to study the feasibility of using a real-time refractometer, which measures dissolved dry solids, to measure wash loss and monitor the performance of brown stock washing systematically, and then be able to take control of the process by using the results of enough such measurements. In addition, different washers' operational performance were studied by performing stepwise tests and monitoring the results using refractometers. The results show that refractometer measurement works with enough accuracy under very demanding process conditions to reliably measure liquid and pulp streams' dissolved dry solids. Therefore, reliable wash loss measurement can be undertaken using refractometers, once calibration is carried out for the wood species and the installation's characteristics. By utilising the results from three refractometers' consistency and flow rate measurements, it was possible to create a measurement system able to calculate the effectiveness of a single washer accurately and in real time. These refractometers can also be used to determine a washer's optimal operating point. Adjusting a washer's operation towards more efficient operation succeeded in reducing the amount of wash loss to the oxygen delignification and bleaching stages, increasing the dry solids content to the evaporation stage and thus achieving significant economic savings. As continuation has considered to match the filtrate balances over the washers by using four or at least three real-time measurements. Moreover, utilising the refractometer in bleaching washing and calculating the wash loss effects on the bleaching costs has been considered. The work also involves utilising refractometers for very low concentrations in WWTP.
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    Environmental engagement of Finnish printing companies
    (Aalto University, 2015) Viluksela, Pentti; Pohjola, Tuula, Dr., CRnet Oy, Finland; Puunjalostustekniikan laitos; Department of Forest Products Technology; Kemian tekniikan korkeakoulu; School of Chemical Technology; Dahl, Olli, Prof., Aalto University, Department of Forest Products Technology, Finland
    Growing environmental awareness of citizens, consumers and organizations has led to stronger demands that industrial companies should manage and reduce their environmental impacts and engage in environmental communication. The environmental activities of the Finnish printing industry have not been studied in detail – especially the contributions of many micro and small enterprises have been under-represented or even totally absent from earlier studies. The purpose of this study was to gain an up-to-date snapshot of the environmental activities of Finnish printing companies by assessing their use of environmental and sustainability management tools and to evaluate the extent and quality of their environmental communication. All identifiable Finnish printing companies in the prepress, printing and finishing subsectors were included in the study sample. Secondary data sources of commercial databases, certification bodies, industry associations and authorities were accessed to collect basic company information, financial data and information on the usage of sustainability tools. Websites of the Finnish printing companies were used for analyzing the environmental communication. The study involved 970 companies, out of which 83.7% were micro enterprises of less than 10 employees. Only 86 companies (8.9%) used at least one third-party certified environmental and sustainability tool and 142 companies (14.6%) provided at least some environmental information on their websites. The environmental web content was generally found to be unimpressive. Greenwashing – mostly vague or non-proven environmental claims –was encountered on 58 websites. In order to quantify environmental engagement, novel calculation models for tools usage and environmental communication were developed. The extent of environmental engagement displayed a moderate correlation with company net sales but no correlation with profit. Those companies operating in the printing subsector, compared to prepress and finishing, were more environmentally active. From the financial point of view, over 80% of the business volume of the industry originated from strongly or moderately environmentally engaged companies. This study revealed that environmental engagement of the larger Finnish printing companies is at a good level, but almost non-existent among micro enterprises. Smaller companies should be encouraged to benefit from the most suitable of the many management tools available. Environmental communication has an impact on the image of the whole print sector; industrial associations could support the adoption of a sector-wide active and substantive communication approach, including benchmarking and training inputs.
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    Promoting waste prevention in industry – search for policy instruments
    (Aalto University, 2016) Lilja, Raimo; Puunjalostustekniikan laitos; Department of Forest Products Technology; Environmental Technology within Process Industry; Kemian tekniikan korkeakoulu; School of Chemical Technology; Dahl, Olli, Prof., Aalto University, Department of Forest Products Technology, Finland
    The research challenge was to assess the benefits and limitations of using the concept Material Efficiency (MEf) as a proxy for the concept of Waste Prevention (WPr) in the context of designing policy instruments to promote WPr actions in the industry. The materials and methods for the thesis included studies of the statistics of hazardous industrial waste, observations from several cases of policy design processes in Finland, stakeholder interviews, an empirical study of environmental permits and elements of discourse analysis and policy evaluation. The results of the thesis support the view that MEf discourse can be used to translate the WPr goal into practice, with some limitations. A typology of MEf categories was developed and used as a tool for assessing the present scope of regulating WPr and MEf in a sample of environmental permits for industry in Finland. The study verified that in practice the waste hierarchy is not applied in most of the permits. The Industrial Emission Directive gives permitting authorities the mandate to regulate many categories of MEf. MEf is an important aspect of best available technique. There are legal and pragmatic limits to regulating MEf through permits. MEf policy is more complex than traditional pollution abatement policy because the use and choice of materials is directed by powerful sector-specific practices and policies, whereas WPr is more purely an environmental concern. Maximizing MEf in one phase of the life cycle of a product may not be the optimal solution. The findings suggest that a negotiated agreement or "green deal" could be feasible in Finland for promoting certain elements of circular economy. The case studies illustrate that the framing of MEf affects the choice of policy instruments. The thesis concludes that WPr would be easier to promote if it were clearly distanced from waste policy. Both quantitative and qualitative WPr can be better promoted through the concept of MEf in the broader cleaner production or circular economy context as compared to the current linkage with waste management policy.